Investigating the Inconsistency of Errors Between CAs in the Wild for Trustworthiness Evaluation in Cross-Domain Authentication

Motivated by challenges in cyber-physical systems (CPS), this paper investigates the inconsistency of errors between certification authorities (CAs) to evaluate trustworthiness in cross-domain authentication. CPS integrates physical space and cyberspace through interconnected devices. Cross-domain authentication is essential for CPS, enabling dynamic communication between devices from different domains. Public key infrastructure (PKI) facilitates this authentication as multiple CAs bind public keys to device identities. However, recent research on evaluating the trustworthiness of PKI focuses on a single CA and overlooks the relationships between CAs. We analyze the inconsistency of errors between CAs based on public key certificates collected from the wild via Censys. Our findings reveal that CAs with inconsistencies often lack essential access information for CAs, risking incomplete certificate verification and communication with fraudulent devices. This research highlights the importance of considering CA relationships in trustworthiness evaluations for secure cross-domain authentication in heterogeneous CPS environments.